The invention relates to a switching drum seal for a switching drum or drum controller for opening and closing an intake pipe in an intake manifold system of a multi-cylinder internal combustion engine.
U.S. Pat. No. 6,138,628 (=DE 197 12 680) discloses a seal for a switching drum for sealing an intake pipe in an intake manifold system of a multi-cylinder internal combustion engine. The switching drum is disposed in a longitudinal bore intersecting at least two intake pipes and has a switching drum seal mounted thereon for each intake pipe. The known switching drum seal has two parallel circumferential sealing sections with circumferential sealing surfaces and two parallel axial sealing sections with axial sealing surfaces. The axial sealing sections connect the two circumferential sealing sections to each other. The sealing surfaces of all the sealing sections are in resilient contact with the inner wall of the switching drum bore in which the switching drum is received and, depending on the position of the switching drum, close off an intake pipe. To ensure sealing contact of the sealing surfaces to the inner wall of the switching drum bore, the circumferential sealing sections are designed to extend beyond the axial sealing sections with a partially-circular leg on both sides, such that in the installed state the switching drum seal completely encircles the switching drum. The two spring-type legs are radially resilient and thus press the sealing surfaces of all the sealing sections against the inner wall of the switching drum bore.
The known switching drum seal has the disadvantage that it is complex to assemble since the spring-type legs of the sealing element must first be spread apart before the switching drum seal can be laterally slipped onto the switching drum. A further drawback is that the switching drum seals get tangled during transport in bulk containers and must be manually separated prior to assembly.
Additional switching drum seals are disclosed in U.S. Pat. No. 6,588,389 (=DE 199 44 108) in which separate sealing elements are used to provide the seal in circumferential direction and the seal in axial direction. The sealing elements extending in circumferential direction are configured as split rings that enclose the switching drum along the periphery. A disadvantage of these switching drum seals is the increased assembly complexity because of the multipart design. Assembly is made more difficult because the sealing elements extending in circumferential direction have to be spread apart before they can be slipped onto the switching drum.